US2253824A - Caster for application to vehicles - Google Patents

Description

Aug. 26, 1941.

C. R. TOWNSEND ETAL I CASTER' FOR APPLICATION TO VEHICLES 2 Sheets-Sheet 1 Filed Feb. 8, 1940 ,Zhvenfors. RLES K2429 Tawwspvo 61.4005 GA; 714452 7bwivsawo- 'Aug. 26, 1941 -c.' TOWNSEND ETAL 53,8 4 CASTER FOR APPLICATION T0 VEHICLES Filed- Feb. 8, 1940 2 Sheets-Sheet 2 Char/es lZz/pb 5 RIMS end C/a u'de Marlmar onmse nd MVf/YiU/f I Patented Aug. 26, 1941 OAS'I'EB FOB APPHCATION TO VEHICLES Charles Ralph Townsend and Claude Mortimer Townsend, Birmingham, England Application February 8, 1940, Serial No. 317,919 In Great Britain February 3, 1939 Claims. (01. 16-85) This invention relates to a swivellingcaster oi the kind in which the swivelling of the caster and the revolution of its wheel are braked simultaneously by means oi a single control device.

In this kind of caster it has been proposed to brake on the periphery of the wheel by a spoonshaped arm, and on the swivelling member by engaging tooth suriaces provided in stationary and swivelled parts, both moved simultaneously by foot operation such as from a pedal. Apart from mechanical and other disadvantages, this known arrangement of braking mechanism does not admit of two or more casters being coupled to achieve the desideratum of collective and simultaneous braking of the swivellings and revolutions of the wheels.

The primary object of the invention is to provide a caster having improved brake mechanism and operating means therefor and also to provide in a simple and inexpensive manner for the collective and simultaneous braking of two or more casters especially, but notexclusively, under "dead man's" control means.

The invention comprises the combination of parts hereinafter particularly described with relerence to the accompanying explanatory drawings and specifically referred to in the appended claims.

Fig. l is a perspective view of a trolley fitted with casters and control means according to the invention.

Fig. 2 is a vertical section taken on the chainlines a, a, Fig. 6, the braking member being illustrated in its application to a single caster. Fig. 2 represents a modified form 01 the brake operating means as illustrated in Fig. 5.

Fig. 3 is a detail of the brake shoes and associated elements.

Fig. i is an elevation of Fig. 3.

Fig. 5 is a side elevation on a larger scale of a pair of casters whose braking members are coupled by a bar for collective and simultaneous operation as in Fig. l.

Fig. 6 is a vertical section oi! Fig. 5, taken on the chain-line h, b.

The caster embodies a body or fork I, carrying a wheel 2, swivelled by its crown 3 on the lower end of a caster peg t, anti-frictional ball bearings 5, d, being provided between the crown 3 and a cap 7 and between the crown I and a fixing nut 8. Mounted on'the outer side of one of thebranche O 01' the swivelled fork i is a vertically slidable bar it slotted at H for engagement with the guide pin i2 screwed into this branch. This its lower end is iointedly connected at It to one end ll of a lever i 6 which lies closely against said branch 9, the other end I i of said lever being cranked inwardly and fixedly carries a cam is. a shank of which has a bearing in a stationary face plate I9 secured to the branch 9 by pins 26. Said cam is is interposed between ends 01' a pair of brake shoes at, pivoted at 22 on said face plate, and whose friction linings are adapted to be expanded into engagement with a braking annulus 24 of the caster wheel 2 against the action of a tension spring 25.

The brake pad l3 co-operates with the circular friction face 26 of a'braking member 21 concentrically mounted about the caster peg l so that said member 21 is capable of linear movement in a vertical plane and is constrained against rotation by means of positive engagement with a hexagon or other non-circular shank 28 forming an immovable extension of said peg.

In the brakes "of!" position, Fig. 2, the braking member 21 is displaceable against the action 0! a compression spring 29 arranged concentrically about the hexagon shank 28 in a sleeved extension of the braking member and abutting against shoulders, 30, 30.

A lug 82 on said sleeve forms an anchorage for an end of a cable 33 of the "Bowden type, adapted to lie-connected to manually operated means.

In Fig. 5, two brake members 21, each associated with a caster and brake mechanism as previously described, are coupled by a bar 34 on which is mounted a control device 35 common to both braking members 21 so that they are operated collectively and simultaneously. This bar has a brake pad it at its upper end while control device embodies a socket 38 pivotally mounted on the bar 34 by its forked end 87 and adapted to slide against the action of a com pression spring 38 over the inverted socket 89 whose mounting plate to is adapted to be anchored to the chassis of a trolley. An end 01' a "Bowden cable 4| is connected to the base of the socket 36 and the other end is adapted to be connected to an operating member.

The application of the coupled brake member system is shown applied to the trolley, Fig. 1, the bar 84 being bent. This trolley is advantageously provided with a pivoted handle 42 operating on the so-called dead man" principle,

in that when it is released by the operator, dual braking on both casters is automatically effected and whenmoved downwardly in the act of pushing the trolley along, the dual brakes are re- 2 leased and are so maintained until the operator takes his hand oil the handle.

The cable or equivalent rod M is shown connected at its upper end to a crank 48 fastened to a cross bar 34 which rotates with the handle 42 on the brackets 45; normally the handle is elevated through the cable by the energy of the spring 38.

In the brakes operating position, Fig. 1, the energy of the spring 38 pushes the socket 38 downwardly and also the coupling bar 34 whereby the braking members 21 press against the brake pads l3 and brake the swivelling movement of the casters. Simultaneously the sliding bars l0, which carry said pads, are caused to move downwardly, whereby an angular movement (indicated by the chain lines on the righthand caster, Fig. 5) is imparted to the levers l8 and the brake-shoe operating cams l8 are partially rotated pressing the shoes 2| against the braking annuli 24 of the wheels. When the handle 42 is pressed downwardly, the cable positively draws the socket 38 upwardly againstits spring 31 and with it the coupling bar 34, so that the coupled brake members 21 are raised simultaneously and the contracting action of the spring 25 on the brake shoes 2| transmits rotary movement in the reverse direction to the cam l8 and thus raises the levers l8 and the operating slidable bars 10, as seen in Fig. 6.

Having now described our invention what we claim and desire to secure by Letters Patent is:

1. A swivelling caster of the type referred to, comprising a support to be fixed to a carriage; a forked-body swivellingly mounted on said support; a caster wheel mounted within the fork of the body upon a horizontal axle of the wheel;

braking means for the wheel arranged concentrically within the structure thereof; a braking member having a circular friction face concentric with the swivel axis of said support, said member being capable of vertical movement on said support and being held from rotation; and means arranged upon the forked body and connected to the braking means to actuate the same,

said last means being disposed in the path of movement of the friction face of the braking member, whereby movement of the latter against the said last means will apply the braking means and prevent movement of the wheel.

2. A swivelling caster of the type referred to, comprising a caster peg to be fixed to a support in vertical position; a forked-body swivellingly mounted about the lower end of said peg; a caster wheel mounted within the fork of the body upon a horizontal axle; braking means for the wheel comprising a, brake-band arranged concentrically within the structure thereof; a braking member having a circular friction face concentric to said peg and being capable of vertical movement on the peg and being held from rotation; a spring for automatically moving the braking member in one direction; and means arranged upon the forked body and operatively connected to the brake-band to actuate the same, said means being disposed in the path of movement of the friction face of the braking member, whereby under spring pressure the latter causes the brakeband to be normally applied to the wheel.

3. A caster as claimed in claim 2 in which said means on the forked body comprises a slidable bar; a brake pad secured to the upper end of said bar facing said circular friction face and a lever to operate the brake-band having one end operating the latter and the other being pivotally connected to the lower end of said bar.

4. A caster as claimed in claim 2 in which said caster peg shank is of a polygon transverse section, whereby said braking member is guided in its movement longitudinally on said shank and prevented from rotary movement.

5. A caster as claimed in claim 2 in which said spring is normally compressed and rests on and tends to force said braking member in a downwardly direction to engage and actuate the means arranged on the fork to apply the brake band.

CHARLES RALPH TOWNSEND. CLAUDE MORTIMER TOWNSEND.

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